In the field of solar energy, single level photovoltaic systems have traditionally been used to generate electricity from sunlight. Such single-level systems typically comprise an array of photovoltaic cells arranged generally within a single plane, and are typically supported by a fixed support, or by a rotating support that is capable of tracking the movement of the sun. Photovoltaic arrays supported by fixed supports are generally configured to collect generally all light, while photovoltaic arrays supported by rotating supports are configured to primarily collect direct light.
Multilevel photovoltaic systems have been more recently developed, and comprise multiple arrays of photovoltaic cells distributed over two or more levels, with the different levels being configured such that both diffuse light and direct light may be collected.
Multilevel photovoltaic systems have been previously described. For example, U.S. Patent Application Publication No. 2010/0012169 to Jensen et al. describes a solar energy system for capturing an increased amount of solar energy in an area. A device for collecting obscured solar radiation and converting it into usable electrical energy includes a major concentrated solar energy system combined with a minor solar energy system. In one embodiment, the minor solar energy system includes a primary mirror, secondary mirror and a second photocell. Primary and secondary mirrors of a minor solar energy system are defined by their location, at least a portion of which may be substantially within the concave region of the secondary mirror of a major solar energy system.
U.S. Patent Application Publication No. 2010/0186798 to Tormen et al. describes a photovoltaic device optical system for enhanced light harvesting with a transparent layer of dielectric material having on one side an array of micro-lenses and on the opposite side a metal reflective film with an array of openings. The micro-lenses focus direct sunlight impinging thereon through the openings, to separate direct sunlight and diffuse sunlight. The photovoltaic device has a first photovoltaic cell system for the exploitation of the direct sunlight located in the opposite hemi-space of the micro-lenses array with respect to the plane of the openings array, and a second photovoltaic cell system for the exploitation of diffuse sunlight, located in the same hemi-space containing the micro-lens array with respect to the plane of the openings array.
German Patent Application No. 102006028932 to Doerr describes a module having one or more photovoltaic elements configured to transmit a portion of light focused by a convergent lens. The module has a reflector spaced from the photovoltaic elements, which have a glass substrate. The photovoltaic elements carry a support element in an adjustable position. The photovoltaic elements have an active layer with a thickness of between 5 and 60 micrometers.
Improvements are generally desired. It is therefore an object at least to provide a novel photovoltaic system.